This proposal requests funds to support travel of scientists to the sixth biannual Gordon Research Conference on Mutagenesis, at Plymouth State College, New Hampshire, on June 20-24, 1988. The purpose of the Conference is to bring together leaders in the field to generate new ideas and new outlooks by providing an opportunity for interactions between these leaders. About 135 attendees are expected from universities, research institutes, industry, and government agencies all over the world. This Conference is in the evennumbered years, alternating with the Gordon Conferences on Genetic Toxicology in odd-numbered years which cover the more applied aspects of the field. In 1988, the Conference on Mutagenesis will emphasize mutagenic mechanisms. The scheduled sessions, and the Chairmen who have agreed to serve, include: Sequence changes in shuttle vectors (Jeffrey Miller, Los Angeles); Sequence changes induced by mutagenesis of the mammalian cell genome (William Summers, New Haven); Mammalian DNA repair and mutagenesis (Tomas Lindahl, London); Yeast DNA repair (Robert Mortimer, Berkeley); Mutagenic processes in prokaryotes (Graham Walker, Cambridge); Mutagenesis and mismatch repair (Miroslav Radman, Paris); In vitro mutagenesis (Bernard Strauss, Chicago); and Mutagenesis by alkylating agents (John Cairns, Boston). The understanding of mutagenic processes is important in assessing the genetic consequences of toxicologic agents. The recent discovery that a critical step in carcinogenesis is activation of an oncogene by mutation (either by gross DNA rearrangements or point mutations) makes the understanding of mutagenic mechanisms a particularly significant matter.